This invention relates to a continuous process for preparing N,N-dialkylaminoalkyl (meth)acrylates by transesterification of an alkyl (meth)acrylate with a dialkylamino alcohol in the presence of catalyst and entrainer to form the N,N-dialkylaminoalkyl (meth)acrylate and byproduct alcohol in which an azeotropic mixture of entrainer and byproduct alcohol is continuously removed from the transesterification, to equipment for performing the transesterification and to equipment and methods for purifying the N,N-dialkylaminoalkyl (meth)acrylate.
A number of previous approaches have been taken for preparing N,N-dialkylaminoalkyl (meth)acrylates. In Japanese Patent Application 2001/172234 A2 a hexane entrainer is used in a series of distillation towers which is washed with water, separated in a decanter, and returned to a column. In Japanese Patent Application 2001/172235 number of serial reaction towers are used with purification column, in Japanese Patent Application 2001/172236 A two columns are used, one which removes excess methyl acrylate and one which removes excess DMAE from the catalyst and other heavy components with an evaporator, US Published Patent Application 2004/0168903 A1 describes using 3 or 4 distillation columns that sequentially react then separate the products, US Published Patent Application 2004/0171868 A1 describes a process in which lower alcohol co-products are removed along with lower (meth) acrylate and is then fed into a plant to convert the alcohol co-products back into methyl acrylate, U.S. Pat. No. 6,437,173 describes using a titanium catalyst along with three distillation columns, Published PCT Application WO 2003/093218 A1 describes a tubular piston reaction technology, U.S. Pat. No. 6,417,392 describes removing alcohol co-products as (meth)acrylate azeotropes, Published PCT Application WO 2007/057120 A1 describes a useful entrainer, Japanese Patent Application 2004/189650 A2 describes a batch process, and Japanese Patent Application 2004/106278 A1 describes a batch process which uses water to facilitate the Michael adduct decomposition.
Despite all of these attempts however there is still a need for a simple cost, effective, high yield method of preparing N,N-dialkylaminoalkyl (meth)acrylates that is a continuous reaction that allows users to add reagents and catalysts to the ongoing reaction as desired.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R.§1.56(a) exists.